# declaration
x <- c(1,2,3)
seq(1,10,2) -> z
rep(x,2)

# index
x <- c(4,5,6,7)
x[3]
x[3] <- 0
x[3]
x[-2]
x[c(2,4)]
x[c(2,4)] <- c(13,14)
x

# operation
x+x
x-2
x*4
x/3
x^-2
x%*%x

# function
mean(x)
sd(x)
var(x)
max(x)
min(x)
median(x)
sum(x)
prod(x)
quantile(x,probs=0.5)
length(x)
range(x)

# comparison
c(1,3,5) >= c(1,4,5)
